1. Filed of the Invention
The invention is directed to devices for calibrating, monitoring and maintaining manufacturing robots, especially welding robots.
2. Description of the Prior Art
Increasingly manufacturing robots, such as welding robots, are being used in industry for repetitive tasks. These robots are programmed to perform a specified manufacturing process. How these robots are integrated into the manufacturing process is crucial in taking full advantage of their unique advantages.
Manufacturing robots are provided with various pivoting joints, so that they can be manipulated into various configurations. For example, a second member maybe pivotally coupled to a first member. An encoder calculates the rotational position of the second member relative to the first member and provides a position signal to the robot controller. The encoder is provided with an absolute zero reference point from which the relative movements of the members can be calculated. Sometimes the encoders become broken or inaccurate. In removing an encoder from a robot, the first and second members are moved into a position where the encoder is at its absolute zero reference point and the encoder is removed. During this removal operation, the angular position of the first and second members maybe accidentally changed requiring the robot to be reprogrammed once the new encoder is installed. Such an occurrence results in additional downtime.
Welding robots are provided with welding torches having a series of shielding gas nozzles. Sufficient flow of the shielding gas during the welding process is essential for quality welds. If shielding gas flow is blocked or insufficient, defective welds are produced. Robotic welding systems typically monitor gas flow upstream from the nozzles and are incapable of detecting diversion of gas from the torch. Therefore the operator must be constantly alert for this problem.
In a welding robot, a welding wire is fed through a welding tube and projects past the shielding gas nozzles. If the wire tip is offset more than a small fraction of an inch from its desired location, the resulting weld will be uneven and weak since weld leg length and/or penetration are adversely affected by the offset. There are numerous sources of torch and wire tip misalignment. As such it is important that the alignment of the torch tip be checked periodically.